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Biochemistry Final Exam > Lecture Notes > Flashcards

Lecture Notes Flashcards

(99 cards)

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1
Q

What are bypass reactions

A

Reactions that run independent of opposing pathways
Ie opposing pathways for reactions that are irreversible

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2
Q

Metabolism depends on cells sensing ___ and ____.

A

Environment and communication between cells

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3
Q

What is an example of bypass pathways?

A

Glycolysis and gluconeogenesis

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4
Q

How can bypass pathways occur without causing a futile cycle?

A

Different enzymes used

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5
Q

Irreversible reactions with a high change in G are targets for what?

A

Regulation

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6
Q

Where does the cell usually regulate in a pathway

A

At the beginning or end
Either the committed step or rate limiting step

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7
Q
A
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8
Q

Enzymes for reactions are regulated by ___ mechanisms, such as ___.

A

One or more, PFK-1

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9
Q

What are the two types of regulatory strategies?

A

Internal: substrate availability, cofactor availability, activators/inhibitors, feedback inhibition, feedforward activation
External: hormone/chemical messenger

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10
Q

What can influence how a pathway responds to certain messages.

A

Physiological: fasting, exercise, feeding, glucose levels, oxygen levels, fatty acid levels
Cells: liver cells , adipocytes, skeletal muscle cells

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11
Q

When is glycolysis activated?

A

By carbohydrates when cells need energy and glucose is available

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12
Q

Does glycolysis need oxygen to function?

A

No

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13
Q

Will glycolysis occur when exercising or stationary?

A

Independent of either

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14
Q

When will fermentation be activated?

A

By carbohydrates when the body needs quick energy and glucose is available

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15
Q

Does fermentation need oxygen to occur?

A

No

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16
Q

Will fermentation increase or decrease during exercise?

A

Increase

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17
Q

When will pyruvate oxidation be activated?

A

By carbohydrates when there is a high energy need

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18
Q

Does pyruvate oxidation need energy to occur?

A

Yes

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19
Q

Is pyruvate oxidation fast or slow?

A

Slow

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20
Q

When will the citric acid cycle occur?

A

By carbohydrates when there is a high energy need

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21
Q

Does the citric acid cycle need oxygen into order to occur?

A

Yes

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22
Q

Is the citric acid cycle slow or fast?

A

Slow

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23
Q

When is gluconeogenesis activated?

A

By carbohydrates when there is a decrease in blood glucose levels due to being in a fasting state

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24
Q

Does gluconeogenesis need oxygen in order to occur?

A

No

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25
When is glycogenesis activate?
By carbohydrates when blood glucose levels are high usually when in a fed state
26
Does glycogenesis need oxygen in order to occur?
No
27
When is glycogenolysis activated?
By carbohydrates when blood glucose levels are low usually when in a fasting state
28
Does glycogenolysis need oxygen in order to occur?
Yes
29
Will the rates glycogenolysis increase or decrease during exercise?
Increase
30
When will fatty acid oxidation be activated?
By fats when blood glucose levels are low no matter if the body is in a fasting or fed state
31
Does fatty acid oxidation need oxygen in order to occur?
No
32
Will the rates of fatty acid oxidation increase or decrease during exercise?
Increase
33
When will lipolysis be activated?
By fats when energy levels are low, low blood glucose levels, or a decrease in fatty acids usually during intense exercise
34
Does lipolysis depend on oxygen in order to occur?
No
35
When is lipogenesis activated?
By fats when energy levels are high, blood glucose levels are high, or the amount of fatty acids are high
36
When is ketogenesis activated?
By fats when blood glucose levels are low
37
Does lipogenesis depend on oxygen in order to occur?
No
38
What does pathway activated depend on?
Cell types, glucose or TAGs, oxygen, and energy states
39
Does lipogenesis depend on oxygen in order to occur?
No
40
Which hormones regulate pathways?
Glucagon, insulin, and epinephrine They amplify the second messengers and alter activity of metabolic enzymes
41
When will insulin be activated?
When there is an abundance of energy
42
When will glucagon be activated?
When there is a scarcity of energy
43
Where does insulin bind to?
To a receptor which activates PP1 or PP2 and triggers cascade and dephosphorylates enzymes
44
45
Where does glucagon bind to?
Binds to a receptor and activates kinases (PKA) which phosphorylates metabolic enzymes
46
What does insulin do to glycogenolysis in liver cells?
Decrease activity
47
What does glucagon do to glycogenolysis in liver cells?
Increase activity
48
What does insulin do to glycogenolysis in muscle cells?
Decreases activity
49
What does glucagon do to glycogenolysis in muscle cells
Nothing
50
What does insulin do to glycogenesis in the liver?
Increase activity
51
What does glucagon do to glycogenesis in the liver?
Decrease activity
52
What does insulin do to glycogenesis in muscle cells?
Increase activity
53
What does glucagon do to glycogenesis in muscle cells?
Nothing
54
What does insulin do to glycolysis in liver cells?
Increase activity
55
What does glucagon do to glycolysis in liver cells?
Decrease activity
56
What does insulin do to glycolysis in muscle cells?
Increase activity
57
What does glucagon do to glycolysis in muscle cells?
Nothing
58
What does insulin do to gluconeogenesis in liver cells?
Decrease activity
59
What does glucagon do to gluconeogenesis in liver cells?
Increase activity
60
What does insulin do to gluconeogenesis in muscle cells?
Nothing
61
What does glucagon do to gluconeogenesis in muscle cells?
Nothing
62
What does insulin do to fatty acid oxidation in liver cells?
Decrease activity
63
What does glucagon do to fatty acid oxidation in liver cells?
Increase activity
64
What does insulin do to fatty acid oxidation in muscle cells?
Decrease activity
65
What does glucagon do to fatty acid oxidation in muscle cells?
Nothing
66
What does insulin do to fatty acid synthesis in liver cells?
Increase activity
67
What does glucagon do to fatty acid synthesis in liver cells?
Decrease activity
68
What does insulin do to fatty acid synthesis in muscle cells?
Nothing
69
What does glucagon do to fatty acid synthesis in muscle cells?
Nothing
70
What happens to glycogen phosphorylase when insulin is activated?
1. Activates protein phosphatase -1 2. PP-1 inhibits phosphorylase kinase 3. Phosphorylase kinase inhibits glycogen phosphorylase
71
What happens to glycogen synthase when insulin is activated?
1. Activates phosphatase 2. Phosphatase inhibits glycogen synthase B 3. Glycogen synthase B inhibits glycogen synthase A
72
What happens to glycogen phosphorylase when glucagon is activated?
1. Glucagon activates cAMP 2. cAMP activates protein kinase A 3. PKA activates phosphorylase kinase
73
What happens to glycogen synthase when glucagon is activated?
1. Glucagon activates PKA 2. PKA inhibits glycogen synthase A 3. Glycogen synthase A inhibits glycogen synthase B
74
PFK-1 and F-1,6-BPase are controlled by what allosteric effector?
F-2,6-BPase
75
What is F-2,6-Bpase made from?
Bifunctional enzyme
76
Which enzyme is the substrate for bifunctional enzyme and PFK-1?
F-6-P
77
F-6-P is the product of which enzyme?
F-1,6-BPase
78
The bifunctional enzyme cannot be found in which two pathways?
Glycolysis and gluconeogenesis
79
The activity of bifunctional enzyme is regulated by what hormones?
Insulin and glucagon
80
During glycolysis, describe what happens to F-6-P.
When insulin is activated, there will be high levels of F-2,6-BPase with a strong affinity for PFK-1 as its substrate When glucagon is activated, there will be low levels of F-2,6-BPase with a weak affinity for PFK-1 as its substrate
81
Will k50 be lower or higher when there is a decent amount of F-2,6-BPase when insulin is activated?
Lower
82
During gluconeogenesis, describes what happens to F-1,6-BPase.
When insulin is activated, there will be low levels of F-2,6-BPase and will have a weak affinity for F-1,6-BPase as its substrate When glucagon is activated, there will be high levels of F-2,6BPase and will have a strong affinity for F-1,6-BPase as its substrate
83
Will k50 be lower or higher when there is a decent amount of F-1,6-BPase when glucagon is activated?
Lower
84
Is the skeletal muscle isoform of pyruvate kinase influenced by hormones like the ones in the liver?
No it is not
85
Which hormone controls the isoform of pyruvate kinase in the liver?
Glucagon only *phosphorylation inhibits activity*
86
During fatty acid synthesis, which enzyme is targeted by hormones?
ACC because it controls malonyl CoA formation Insulin activates ACC Glucagon inhibits ACC
87
What are the two isozymes of hexokinase?
Hexokinase II found in skeletal muscle Glucokinase/hexokinase IV found in liver
88
Will hexokinase II or IV have a higher affinity for glucose?
Hexokinase II because skeletal muscle needs to be able to contract regardless of glucose levels
89
Which metabolic enzymes act as allosteric activators during glycolysis and slow respiration?
AMP, ADP, and pyruvate
90
Which enzyme activates PFK?
AMP
91
Which enzymes activate pyruvate dehydrogenase?
ADP and pyruvate
92
Which enzyme activates isocitrate dehydrogenase?
ADP
93
Which enzymes act as allosteric inhibitors in glycolysis and slow respiration?
ATP, citrate, acetyl CoA, NADH, and succinyl CoA
94
Which enzymes inhibit PFK?
ATP and citrate
95
Which enzymes inhibit pyruvate dehydrogenase?
ATP, acetyl CoA, and NADH
96
Which enzymes inhibit isocitrate dehydrogenase?
ATP and NADH
97
Citrate is an allosteric activator of what enzyme during lipogenesis?
ACC
98
Fat acids are an inhibitor of what enzyme during lipogenesis?
ACC
99
How does malonyl CoA inhibit fatty acid oxidation?
By blocking carnitine accyltransferase It prevents the futile cycle of fatty acids to acyl CoA system

Biochemistry Final Exam (4 decks)

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